1. Field of the Invention
The present invention relates to a method and device for painting right and left side outer panels of an automobile body.
2. Description of the Related Art
Painting an outer panel of an automobile body is generally carried out by rotary type electrostatic spray painting devices located, for example, on the right and left of and over an assembly line along which the automobile is moved, and a portion of the outer panel in front of the electrostatic spray painting device is sprayed with paint as the panel passes in front of the painting device.
Portions of the right and left side outer panels situated over the front and rear wheels of an automobile chassis have a shorter vertical length than other portions, and to paint these shorter portions, commonly the spray heads of the electrostatic spray painting device are located above and below a central horizontal plane of the side outer panels of the body to be painted (Japanese Unexamined Patent Publication No. 54-11945). In this construction, a distance between the outer panel and the spray head is always constant, and therefore, the line of force of the static electricity of the particles of paint is stable, and thus a good painted surface is obtained. Since, however, the side outer panels are divided into 2 or 3 portions for painting, 4 to 6 spray heads are necessary for one coating, and therefore, the painting system requires a large space in which to locate so many spray heads, and thus equipment costs become relatively high.
An electrostatic spray painting device disclosed in Japanese Examined Patent Publication No. 59-21670 is constructed in such a manner that the spray heads move up and down along a vertical line to enable side outer panels to be painted by one spray head, so that the number of spray heads needed by the painting device is drastically reduced. However, in this painting device, since the spray head moves away from the side outer panel during reciprocation of the spray head, because of a configuration of the side outer panel, the electrostatic charge of the paint particles may be lost. In this case paint particles that have lost their electrostatic charge will adhere to the side outer panel and the quality of the painted surface thereof is degraded.
Japanese Unexamined Patent Publication No. 58-81457 discloses a construction in which paint is sprayed onto the side outer panels by spray heads moving along an outline of the panels.